Expansion absorber



Aug 9, 1932 v J. V. G IESIFER 1,870,902

EXPANS ION ABSORBER Filed Deo. 17, 1927 LttomcllS Patented Aug. 9, 1932 UNITi-:Dv 'STATI-:s PATENT [or-FICE JEAN V. GIESLEB, OF KNOXVILLE, TENNESSEE, ASSIGNOR THE FULTON SYLPHA'ON' COMIANY,`F KNOXVILLE, TENNESSEE, A CORPORATIN OIF DELAWARE EXPANSION YABSORIBIEXB' Application led December 17, 1927.` Serial No. 240,880.

This invention relates to a method and means for maintaining pressure within a container within predetermined limits.

Where it is desired to maintain a certain pressure Within a container for'substantial periods, considerable diiculties have heretofore been encountered due to gradual losses of pressure f from leakage, absorption, changes in temperature, and the like. For

example, in high tension cable installations,

where the ends of two adjoining cable sections are connected, it has been customary to insulate the joint by attaching a sheath to the cables on either side of the joint and -to 16 fill the same with heavy oil or other suitable insulating medium under considerable pressure. It has been found in practice that in time the leakage losses, absorption losses and the like, will so reduce the pressure of the 20 insulating medium that the insulating ei'ect thereof is seriously impaired and when subjected to high tensionsthe joint may break down. The same difficulties are also encountered in many other cases wherein closed conliw tainers, filled4 with some substance or substances, are requiredpto be maintained at or above a certain predetermined pressure.

It has been proposed heretofore to overcome these disadvantages by exerting on the so substance under pressure a substantially constant external force by the provision of suitable external means su'cn as a weighted piston and the like adapted to exert a pressure on the medium within the container. Such means are, however, objectionable for many reasons.- The integrity and strength 'of the container are inevitably impaired, and the possibilities of leakage, fracture of the container, etc., are greatly increased. Furthermore, where considerable pressure must be maintained, the method of maintaining the pressure b the use of Weights and the like as externa pressure exerting means becomes impracticable, since many diliculties are ining member with a sutliciently tight fit to- Andr an collapsible means may be employed for volved in providing an efficient apparatus to prevent leaka of such medium over substantial perio s of time. In any case, the use of means external to the container may be objectionable due to requirements of space and ocation of the container, particularly since any gravity actuated means is operative only in a vertical direction. v

One of the objects of the present invention is to obviate the abovedisadvantagcs and to provide a novel method and means for maintaining a desired pressure Within a container which is efficient, reliable and economical.

Another object is to provide a method of Vmaintaining pressure wlthin a container by utilizing the pressure itself to create an internal expanding force which is of the order of said pressure and compensates for losses of said pressure.

Another object is to provide means which: may be entirely enclosed within a container for maintaining the pressure therein within predetermined limits. y

A further object is to provide expansible means which may be subjected to initial compression within the container, wherebythe expansion of such means compensates for vvariations of pressure normally occurring within said container. l

Other objects will appear as thl description of the `inventionproceeds.w

With the above objects in view, the invention, broadly stated, includes the combination with a suitable container of any desired size or type -having therein a fluid medium under pressure, of an expansible and collapsible member placed entirely within said con-v tainer and Vsubjected to an initial compression by the pressure of said luidl medium.

suitable or .desired type of expansible this purpose. Preferably, suchhmeans takes the form of an expansible, and collapsible vessel,which is maintainedin a normal state of expansion by a gaseous medium containedv therein. When such a vessel is placed ina closed container and subjected to ap-ress'urev greater than thepressure of the gaseous -medium contained within the vessel, it will be compressed until the pressure Within the vessel. equals the pressure withoutthe vessel. 100

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If the vexternal pressure is now decreased or lluctuates due to any cause whatsoeverythe tendency of the vessel to ex and to its normal state immediately in an e ort to compensate for the loss thus maintains a pressure within the container which is equal to or greater than the pressure within the vessel in its normally ex anded state. f

or purposes of exempliiication, the accompanying drawing illustrates the invention as applied to a high tension cable joint, but since many otherapplicati'ons of the invention will be readily apparent to those skilled in the art, and the invention may re-4 ceive a variety of embodiments, it is to be expressly understood that the invention is not limited to the application or embodiment shown, or Aotherwisev than bythe terms of the appended claims.

In the drawing, Fig. 1 is a perspective vieW 'showing the arrangementvand assembly of the arts constituting the joint; F ig. 2 is an enar ed longitudinal sectional view of Fig. 1; an Fig. 3 is an enlarged detail of a lilling valve for the vessel shown in Fig. 2.`

In the drawing, wherein like reference numerals indicate like parts throughout the several views, the adjoining ends of two cable sections 1 and 2, each of which may be suitably armored as at 3 are joined or spliced together at 4 to constitute a cable joint. For vthe purpose of insulating said joint, the ends of the two cable sections are enclosed by a sheath 5 of metal or any other suitable material, which is joined to said sections at 6 and 7, on either side of the joint 4, by an" suitable means such as sweating or sold'e The sheath 5 thereby encloses a space 8 so as to constitute a fluid-tight container which may be filled with an insulating medium such as heavy oil or grease.

In practice it is necessary that the space 8 be placed and maintained under considerable pressure, and to this end suitable means are provided which will compensate for any loss of pressure, such means comprising an expansible and collapsible vessel placed within the space 8. In the form shown said vessel comprises two deeply corrugated, expansible and collapsible walls 9 and 10, preferably of resilient metal, the ends of each .of said walls being attached to two annular heads 11 and 12 in any suitable manner, as' by soldering or brazin An annular space 13 is therebv forme which constitutes a completely sealed, iuid-tight vessel. Y

The space 13 is preferably filled with any .suitable mediumv such as gas, `under an initial pressure determined byl the requirements hereinafter set forth. To this end the head 12 is provided with a boss 14, having an ope g 15 (Fig. 3) communicating with the interior of the vessel, in which is inserted a suitable filling valve 16. The valve; lma'y be of any suitable type, and in the ring.

seated in a recess formed in the valve member 19. The spring 24 normally maintains the-valve 21 closed. YWhen it is desired to charge the vessel 13, the outer end of valve stem 22 is depressed, thereby opening the valve 21, while the fluid is beingforced into the vessel, and as soon as the stem 22 isreleased, the spring 24 wllclose the valve to revent escape of the fluid from the vessel.

en charged, the body 16 may be permanently closed byl means of a plug 26 and a vsuitable sealing medium 27, such as solder,

wax, paraffin, etc.

It is desirable to prevent undue expansion of the vessel in certain cases, as for example when the vessel is charged with a pressure above atmospheric pressure, and before its installation in the container. For this purpose the vessel is provided with any suitable means for limiting its expansion to a desired amount, and in the form shown such means comprise a tubular member 28, surrounding the cable 1, and having a ared end 29 which engages the head 11 and a flared end 30 which may, for example, engage a ring 31 suitably :scured to the bosses 32 as by means of screws In practice, when it is desired to maintain V the pressure within the space 8 above a certain predetermined amount, the vessel 13 is first charged with a suitable gas or other medium at a pressure equal to the minimum pressure desired within the space 8. The charging of the vessel is accomplished as above described by means of the illing valve, and the vessel is then sealed by means of the plug 26 and seal 27. The vesselis then placed within the sheath 5, and the latter is slid over one end of the cable while the splice is being made. When the splice is completed, the sheath 5 is placed in position and preferably sweated or soldered to the cables 1 and 2. The space 8 is then filled with any desired medium such as heavy oil throughanopening 34 in the sheath 5, which opening is then sealed by means of a plug 35. The pressure within the sheath may be raised to any desired maximum, and as soon as it increases above the desired minimum pressure, to which the. vessel 13 is charged, the latter will be compressed so that the pressure within the vessel will be always maintained equal to the pressure in the space 8. It will be apparent that if any loss of pressure in space 8 occurs,

the vessel 13 Will immediately expand until the pressures are again equalized, and the loss Will thereby be compensated and a pressure maintained which is always above the predetermined minimum.

The particular pressure characteristic of the variation between the maximum and minimum values may be regulated by properly l proportioning the initial volume of gas in the vessel to the final volume of gas therein. This may readily be done by inserting in the vessel `13, preliminary to charging it with gas, a certain amount of any substantially non-com'- pressible substance, which may be either solid,

' 15 semi-solid or liquid. This substance is shown by way of example as a liquid, indicated at 36 i j While the invention has been described with particular reference to a cable joint, it will be readily apparent that it is equally applicable to any container wherein it is desired to maintain a certain definite minimum pressure. As has been seen, the means employed may be entirely enclosed within the container,

25 and thus requires no additional space and interferes in no Way with the normal installation and operation of the container itself. Once installed, the device is entirely selfoperative, and requires absolutely no attention. At the same time, it will function over long periods of time, maintaining an accurate andv well-defined minimum pressure Within the container in spite of temperature variations` leakage, absorption, or any other cause 35 tending to reduce the pressure therein. While in the examples given, relatively small pres'- sures W1ll be encountered. the invention is just as serviceable and efficient for high pressures, the only requirements being that the 40 size andstrength of the collapsible vessel be properly proportioned in view of the use to which it is to be put. j

Another advantage of the invention is that the expansive force is created by the pressure which is to be maintained, and may therefore made of the order of sueh pressure without dlfiiculty. For example. if external pressureexerting means are'employed, it is almost impossible to provide suitable operating means which will exert large pressures steadily and constantly over long .periods j of time and.

without care or attention. On the other hand, where the force desired is created by the initial pressure placed upon the medium to be maintained under pressure, this difficulty is entirely avoided; At the same time all packed joints and sliding fits as between cylinders and pistons are eliminated and the chances of leakage losses thereby greatly re.

ducedi The inventionis moreover extremelv simple in construction and design, is reliable and'eiiicient in operation, and is economical and inexpensive to construct. u l

While the invention has been illustrated and described with considerable particui readily occur to those skilled in the art, and

larity, for the purposes of proper explana-l tion, it will readily be apparent that the invention is not limited to the embodiments shown, but that other embodiments will now that changes in the construction, arrangement, and assembly of the parts may be made Without departing from the spirit of the invention. Reference is therefore tobe had to the appended claims for a definition of the limits of the invention. e

What is claimed is:

l. The combination with a cable joint, of a sheath enclosing said joint, a pair of tubular corrugated Walls surrounding said cable/and constituting a collapsible and expansiblevessel, the space between said Walls being charged with a fluid medium under superatmospheric pressure and said sheath being charged with an insulating medium under 85 pressure, and means associated with Asaid Walls to limit expansion thereof. y

2. The combination With a cable joint of a sheath enclosing said joint charged With insulating medium underpressure, a pair of annular heads surrounding said cable Within said sheath. and inner and outer tubular, corrugated walls operatively connected with said l heads to constitute a fluid-tight vessel, a tubular supporting member for said vessel extending through said heads and having lianged ends, said supporting member being adapted to be slipped on said cable, said vessel containing a fluid medium normally under superatmospheric pressure and partially collapsed 100 by the pressure in said sheath but tending to expand'and compensate for losses of pressure in said sheath.

3. An expansible andcontractible unit for maintaining the pressure of a fluid in a container comprising an annular HeXible vessel containing an expansible fluid, a tubular supporting member having flared ends and an annular head at each end of the vessel surrounding the tubular supporting member, said flared ends of the tubular member limiting the expansion of said vessel.

4. In apparatus of the class described, the combination of a container adapted to hold a fluid under pressure, means Within the container for maintaining the fluid pressure comprising an expansible and contractible vessel containing .an expansible fluid, a tubular supporting member having fiared ends, and an annular head at each end of the vessel surrounding the tubular supporting member, said flared ends of the tubular member limiting the expansion of said vessel. A

5. In apparatus of the class described, the e combination of a container adapted to hold a fluidvunder pressure, means Within the container for maintaining the Huid pressure com-l prising a vessel containing an expansible fluid and formed by a pair of cylindrical'icor- -rugated walls joined at the ends by annular ISG heads, and a tubularusupporti'ng member eX- tending through the annular heads and having flared ends for limiting the expansion of said vessel.

6.111 Combination with a @able joint, a

sheath enclosing said joint and containing an insulating medium, and an expansible and contractible unit for maintaining the Huid in the sheath under pressurecomprising an annular flexible vessel Within .said sheath containing an expansible Huid under pressure, a tubular supporting member having flared.

ends, and an annular head at each end of the Y vessel surrounding the tubular supporting member, said unit adapted t0 be irst slipped over the end of the cable in advance of the insulating fluid being forced into the sheath under pressure and partially collapsing the vessel, the expanding Huid Within the vessel at all times vmaintaining the pressure of the insulating fluid above a predetermined minimum.

7 In combination with a cable joint, a sheath enclosing said joint and containing an insulating medium, and an expansible and contractible unit for maintaining the Huid in the sheath under pressure comprising a vessel containing an expansible fluid formed by a pair of cylindrical corrugated walls joined at the ends by annular heads, and a.` tubular supporting member extending through the annular heads and having liared ends for limiting the expansion of said vessel, said unit being adapted to 'be slipped on said cable end after which the insulating Huid may be forced into the sheath under pressure 'and partially colla singl the vessel, the expanding luid w1th1n the vessel at all times maintaimng the pressure of the insulating Huid above a predetermined minimum.

In'testimony whereof I havesigned this specification. Y JEAN V. GIESLER., 

